The fear of missing something weighs heavily on every doctor's mind. But the stakes are highest in the ER, and that fear often leads to extra blood tests and imaging scans for what may be harmless chest pains, run-of-the-mill head bumps, and non-threatening stomachaches.

Many ER doctors say the No. 1 reason is fear of malpractice lawsuits. "It has everything to do with it," said Dr. Angela Gardner, president of the American College of Emergency Physicians.

The fast ER pace plays a role, too: It's much quicker to order a test than to ask a patient lots of questions to make sure that test is really needed.

"It takes time to explain pros and cons. Doctors like to check a box that orders a CT scan and go on to the next patient," said Dr. Jeffrey Kline, an emergency physician at Carolinas Medical Center in Charlotte, N.C.

"Our society puts more weight on technology than on physical exams," Gardner said. "In other words, why would you believe a doctor who only examines you when you can get an X-ray that can tell something for sure?"

Refusing those demands creates unhappy patients. And concern that unhappy patients will sue remains the elephant in the emergency room.

ER physicians are among the top 10 specialists most likely to be sued for malpractice, according to leading doctor and insurers groups.

The Physicians Insurers Association of America, which represents almost two-thirds of private practice doctors, lists more than 600 lawsuits against ER doctors nationwide between 2006-08. That's about 3 percent of their clients.

Statistics vary by region, and chances of being sued generally are greater for several other specialties, including obstetricians, surgeons and internists.

Still, the risk for a malpractice suit remains high in the ER because of the unique setting.

In a busy emergency room, "when all hell is breaking loose, not a lot of doctors feel they can take the time to sit down with the patient" and build rapport, said Texas family physician Dr. Howard Brody, an outspoken critic of excessive medical care.

The result can be extra costs, and potential harm — including side effects from unneeded drugs and increased chances for future cancer from excessive radiation.

No one tells patients after a CT scan that the test "just imparted three years of radiation to your body as well as significant stress on your kidney, and Medicare just got charged lots of money," Kline said.

Gardner, who works in a Dallas emergency room, said she tries to talk patients out of tests she thinks they don't need, but usually without success.

There are more than 116 million ER visits each year nationwide, national data suggest, and research suggests the number of visits is rising.

The most common reasons adults go to emergency departments are abdominal or chest pain. Both can mean something harmless, or deadly.

To determine which it is, ER doctors turn to X-rays, CT scans and other imaging tests. In 2006, these were done for almost half of all emergency visits; blood tests were ordered for more than a third of ER visits; medicine, including antibiotics, was given to 75 percent of patients.

One of doctors' biggest concerns with belly pain is appendicitis, and CT scans can confirm it. But the scans often are done in patients without classic symptoms.

Patients with suspicious abdominal pain used to go straight into the operating room, where surgeons opened them up to find appendicitis — or rule it out. Dr. Angela Mills of the University of Pennsylvania said CT scans have reduced unnecessary surgeries, "but I think the pendulum has gone to the other side." The trade-off is fewer surgeries and hospitalizations versus a test that costs several hundred dollars but which involves lots of radiation.

Mills is studying a blood test that would detect a marker for appendix inflammation, which might avoid the need for CT scans, and would be safer and cheaper, too.

On a recent day at Cook County's Stroger Hospital in Chicago, 50-year-old Teri Moore sought treatment for abdominal pain. A smoker with a hacking cough, the thin, auburn-haired woman had persistent vomiting and hadn't eaten in three days.

Moore's symptoms suggested a stomach ulcer or inflammation, not appendicitis.

Several blood tests were ordered, to check for anemia and liver function, among other things, said Dr. Jeffrey Schaider. He performed a bedside abdominal ultrasound, looking for gallstones. None showed up. Next Moore got a chest X-ray, looking for possible pneumonia or even cancer. Then she got a CT scan, the Cadillac of diagnostic imaging tests. So did at least 61 of the 385 patients treated in the Stroger ER and trauma unit that day. Doctors there boast that it's the busiest CT scanner in North America, running nearly round the clock. It did 16,623 scans last year.

As for Moore, nothing definitive turned up, and she was sent home.

Was all her testing overkill, or good care?

Moore said she wouldn't second-guess the doctors. "They went to school for it, they should know," she said.

Schaider said the CT scan was needed to rule out appendicitis or an infection, but above all to exclude any emergency, life-threatening condition. "That's our No. 1 thing," Schaider said.

He dismissed the idea of overtesting. "We do what testing we think is necessary," he said. "Most of the time we're really motivated by what benefits the patients most."

Still, he said lawsuit concerns play a role in testing decisions at ERs in publicly funded hospitals like Stroger, too.

The 41-year-old Texas woman sought emergency treatment for chest pain at Christus St. Mary Hospital in Port Arthur, Texas, but doctors didn't think it was heart-related and sent her home. She fell dead of a heart attack several hours later. Her family won a malpractice lawsuit in January.

Meaux was overweight, with high blood pressure and diabetes when she died Oct. 3, 2007. Doctors did two electrocardiograms — a heart test using little sensors placed on the chest and elsewhere. They also checked Meaux's blood pressure, but skipped other heart tests, and sent her home with medicine for high blood pressure and asthma-like symptoms, court documents show.

A jury found Meaux's doctor and the hospital negligent and awarded her family more than $1 million in damages. A hospital spokesman said he couldn't comment because the hospital is appealing the verdict.

"I just don't have any faith in emergency rooms, because I lost a daughter," Licatino said. "They're not doing enough."

However, as many as 95 percent of ER patients with chest pain aren't having a heart attack, so it's more typical that doctors go overboard with testing.

"Often we are testing for that 5 percent," said Dr. Rahul Khare, an emergency physician at Northwestern Memorial Hospital in Chicago.

Patients with suspected heart attacks often get the range of what the ER offers, from multiple blood tests that can quickly add up in cost, to X-rays and EKGs, to costly CT scans, which are becoming routine in some hospital ERs for diagnosing heart attacks.

And the battery of testing may be paying off: A few decades ago insurance statistics showed that about 5 percent of heart attacks were missed in the emergency room. Now it's well under 1 percent, said Dr. Robert Bitterman, head of the American College of Emergency Physicians' medical-legal committee.

"But you still get sued if you miss them," Bitterman added.

Audrey Vernick of Ocean Township, N.J., knows that doctors sometimes overtest. But she also understands their dilemma.

"They're so scared of not catching what might be there," Vernick said. "I can so see both sides of it."

Vernick's 10-year-old daughter, Anna, twisted her ankle in gym class last fall and Vernick couldn't get an appointment with an orthopedic specialist. So she took Anna to the ER just to be safe — a visit that cost about $1,000. The family's insurance covered it.

Anna was limping but could walk and her ankle wasn't swollen or excruciatingly painful. Common guidelines say those symptoms suggest a fracture is unlikely and an X-ray is unneeded. She got one anyway.